ISSUE:

Some vehicles equipped with a 4.6L, 5.4L, or 6.8L engine may exhibit a rough idle/miss after start-up in cold ambient temperatures (less than -12°C/10°F). This may be caused by a roller finger follower(s) being dislodged from the valve. This may result in damage to the camshaft, roller finger follower, valve, retainer, etc. A procedure is now available to service this condition.

ACTION:

Inspect and replace any worn or damaged engine valve components and install new retaining clip and lash adjuster for service. Refer to the following Service Procedure for details.

SERVICE PROCEDURE

Perform normal engine diagnostic routines before opening valve covers. If the valve train is suspect, remove the valve covers and look for Roller Finger Follower(s) (RFF) that may have become dislodged.

Inspect the following parts that may have been damaged by any dislodged roller finger followers:

Cam lobes (chipped or grooved)

Valve stem tips (mushroomed, metal displaced, or bent)

Roller finger followers (chipped or grooved)

Inspect valve guide only if its corresponding RFF or valve stem tip is damaged.

Replace damaged parts as necessary.

If follower(s) are damaged, replaced as necessary, otherwise re-use followers in same location as removed from head.

Remove all intake and exhaust lash adjusters from the engine and replace with service-only Lash Adjusters (YL3Z-6500-AA). Refer to the appropriate Workshop Manual, Section 303-01B for service procedures and tooling necessary to compress the valve springs and remove the roller followers.

NOTE:

REFER TO FIGURE 1 FOR INSTALLATION OF THE NEW RETAINING CLIPS (YL3Z-6A539-AA), TO THE ROLLER FINGER FOLLOWER.

THE CLIP IS NOT REMOVABLE FROM ADJUSTER ONCE IT HAS BEEN SNAPPED INTO PLACE. IF THE ENGINE NEEDS TO BE SERVICED AT A LATER DATE, REMOVE THE RFF BY BENDING UP THE CLIP. LEAVE LASH ADJUSTER IN THE ENGINE WITH THE CLIP WHILE REMOVING THE FOLLOWER. THEN REMOVE THE LASH ADJUSTER FROM THE HEAD AND SNIP/CUT THE CLIP FROM THE LASH ADJUSTER. REPLACE WITH A NEW CLIP ON FOLLOWER DURING INSTALLATION.